They were doing stuff like this in the model car magazines using spray enamel on water and dipping bodies in it for some really cool paint jobs...back in the early '70s. I myself never tried it because my "budget" at the time didn't allow me to squander a can of paint or a model kit. This is just slightly more sophisticated.
I know a guy who does hydro dipping out here in WI. Mostly gun parts, game controllers, little stuff like that. Never seen it on wheels though. Cool idea but like tangledupinblu said, I'd hate to try touching it up after a curb scrape or careless tire mounting.